1. Technical Field
The present invention relates to a shift register circuitry, especially relating to a shift register circuitry including a plurality of stages of shift registers. Each of the plurality of stages of shift registers is configured to provide an unmodified scan signal and a modified scan signal of said each of the plurality of stages of shift registers.
2. Description of the Prior Art
Liquid crystal displays, light emitting diode displays and organic light emitting diode displays are widely used nowadays. In general, the liquid crystal display, light emitting diode display and organic light emitting diode display have a plurality of pixel units, a source driver and a shift register circuitry. The source driver is used to provide a plurality of data signals to the plurality of pixel units. The shift register circuitry includes a plurality of stages of gate driving circuits to generate a plurality of gate signals configured to be fed to the plurality of pixel units, to control the writing operation of the plurality of data signals. Thus, the shift register circuitry is a key element to control the writing operation of the plurality of data signals.
Please refer to FIGS. 1 and 2. FIG. 1 shows a driving circuit 100 of a related art OLED display. As shown in FIG. 1, the driving circuit 100 includes the first switch T1 to the sixth switch T6, the capacitors C1 and C2 and the organic light emitting diode OLED. The first switch T1 is used to receive the data signal Vdata, and the first switch T1 and the fifth switch T5 are controlled by the Nth stage scan signal S_N to be turned on and off. The sixth switch is used to receive the initial signal Vint, and is controlled by the (N−1)th stage scan signal S_(N−1) to be turned on and off. The second switch T2 and the fourth switch T4 are controlled by the enabling signal EM to be turned on and off, and the source end of the second switch T2 is coupled to the voltage source VDD. The Nth stage scan signal S_N and the (N−1)th stage scan signal S_(N−1) are generated by the shift register circuitry in the OLED display and are transmitted to the driving circuit 100.
FIG. 2 is a timing chart showing the operation of the driving circuit 100 in FIG. 1. As shown in FIG. 2, because the Nth stage scan signal S_N and the (N−1)th stage scan signal S_(N−1) are substantially partial overlapping each other as the dotted line shows below “t2”, the OLED may not correctly display colors according to data signals. For example, at the timing t1, when the (N−1)th stage scan signal S_(N−1) is low, the sixth switch T6 will be turned on, which makes the gate end of the third switch have the voltage level of Vint. At the timing t2, when the voltage level of the Nth stage scan signal S_N is low, the first switch T1 will be turned on. Because the sixth switch T6 is not fully turned off at the timing t2, the third switch T3 will synchronously receive the initial signal Vint and the data signal Vdata, and thus making the OLED display improper colors according to the data signal Vdata.